Attn: evildky, need your opinion on a turbo.

[DemonZ]

I got a hold of an HX40W Holset really cheap at an estate sale... The gentleman who had passed away was a huge Z car guy (his name escapes me, I never knew him myself).

Long story short, It needs to be rebuilt and the compressor side blades are a little chewed up, so I would have to replace that at the very least.

The question is, do you think it's worth it, and here's why I ask.

The HX35 has 60/69mm turbinewheel and HX40 64/76mm turbinewheel.

Data from Holset dealer:

HX30Compressor: 68mm or 72mm.Turbine: 8 - 10 cm2

HX35Compressor: 77mm or 82mm.Turbine: 12 - 18 cm2

HX40Compressor: 82mm or 85mm.Turbine: 20+ cm2

I know plenty of people running HX35's and HY35's, but I'm wondering if the HX40 is going to be too big?I have a feeling the lag is going to be pretty bad and it's going to feel like a week has gone by before I get into decent boost.

I havent built the motor yet, I was going to build it to match what ever turbo I decided on. I had originally planned on a t3/t4 or an HX35, but this HX40 just kinda dropped in my lap.

I'm wondering if I should go ahead and stick with this, and just make sure I build the engine accordingly, if I can, or if I should try and find something a little bit smaller.

I still consider myself a novice as far as turbo's go, so any opinions or suggestions would be greatly appreciated.

[evildky]

wow well it looks really buig, and I'd dare to say too big, any idea what the flow rate is? I know the HX and HY 35's are pretty big but still usable on the L28, no deal for autocross but you can get away with one, I worry taht the 40 would be so big it'd be useless anywhere but the drag strip, I suspect ti would take to 5k rpm to spool that beast, if you could get the VE map I could tell you for sure but I'd look for somethign a bit mroe size appropriate

[DemonZ]

wow well it looks really buig, and I'd dare to say too big, any idea what the flow rate is? I know the HX and HY 35's are pretty big but still usable on the L28, no deal for autocross but you can get away with one, I worry taht the 40 would be so big it'd be useless anywhere but the drag strip, I suspect ti would take to 5k rpm to spool that beast, if you could get the VE map I could tell you for sure but I'd look for somethign a bit mroe size appropriate

I'm not sure how accurate this map is, and disregard the red line in the middle, I pulled this off a calculating site, and the red line is supposed to represent the defaulted specs the site had, not sure what engine the default specs are for.

I was figuring that it probably wouldnt spool up till high RPM as well. I've heard of people using a small 20 shot of nitrous controlled by a switch hooked up to the Mass Airflow sensor to help with the initial lag, but... that's not exactly a good solution.

I figured I would open up the intake and exhaust ports on the head and the exhaust manifold... but I dont think it would do much in the grand scheme of things.

I was thinking about upping the displacement to 3.0 regardless of what turbo I went with. But again, not sure if it would help enough, like I siad, my turbo knowldge is limited.

[DemonZ]

I had to dig through my browser history, but here's the turbo calculationg site I pulled the map off of:http://www.squirrelpf.com/turbocalc/

[evildky]

wow, great site, and the turbo isn't as bad as I'd suspected, you are not using it in it's peak efficiency but it's able to spool to 20 psi inside the surge limits, I do fear that bost will climb slowly being outside the peak efficiency area, not the turbo I'd shop for but if you have one laying around and are comfortable fabbing everything up why not

[DemonZ]

cool cool

I have a friend over at Boost Logic running a 600WHP 2JZ (supra) motor in his Z31 slicktop. His car is nuts. Anyway, he stopped by my store today, and I mentioned the HX40, he was thinking it ought to be just about perfect. He's running a similar sized turbo on the 2JZ. I mentioned my concern about when it would spool up, and he suggested that if I have any problems, I should simply take an HX35 hot side and mate it up and make it a hybrid, similar to a T3/T4, and that should solve the issues with spool time.

[evildky]

the holset compressors are not compatible with the garret center sections and exhaust housings

looks like the HX40 is capable of 550 sh whp, your pistons will go long before that

[DemonZ]

the holset compressors are not compatible with the garret center sections and exhaust housings

looks like the HX40 is capable of 550 sh whp, your pistons will go long before that

I was talking about taking an HX35 hot side and making a HX40/HX35 hybrid, similar to how some people take t3's and t4's and make t3/t4 hybrids.

I'll probably aim for about 300whp until I get forged pistons. But once that turbo gets into boost, it ought to be nice.

[evildky]

don't gotget holsets have no internal wastegate so you'll need a fat external wastegate to keep that thing from pumping stupid amounts of air into your engine once ti does get spooled